Answer:
Expression of work done is

Work done to move the sled is given as 187.2 J
Explanation:
As we know that the formula of work done is given as

here we know that
F = 12.6 N
d = 15.4 m

so we will have



let's use first equation of motion to solve this ;
Velocity after 30 seconds = 170 m/s
<span>0.7 meters from the support, or 0.4 meters from the end of the board.
Another way of describing the problem is to have the 450 N person move so that the center of mass of the plank and person system is on the second support. So let's first determine how far from that support the center of mass of the plank is. We can model the plank as a point mass source that's 2.5 meters from either end. So that point mass is 2.5-1.1 = 1.4 meters from the pivot. So let's multiply that radius by the mass, getting:
1.4 m * 225 N = 315 Nm
Now the person will be at just the tipping point when their mass multiplied by the distance equal 315. So let's do the division.
315 Nm / 450 N = 0.7 m
So the person will be at the tipping point when he's 0.7 meter from the support, or 1.1 - 0.7 = 0.4 meters from the end of the board.</span>
Answer:
Normal force of 10,000N
Explanation:
From the question, the weight the car exerts on the pavement is 10,000N.
The pavement exerts upward and perpendicular contact force called normal force on the car to support its weight. Also, the normal force is equal and opposite to the weigh of the car.
Hence the pavement exerts normal force of 10,000N back on the car to prevent it from passing through it.